ABSTRACT
@# Objective: To investigate the effects of antimicrobial peptides merecidin on the biological functions of human lung adenocarcinomaA549 cells and the potential signaling pathways and targets that involved in promoting apoptosis, by studying the changes of phosphorylation levels of proteins in A549 cells after merecidin treatment. Methods: The antibacterial peptide mericidin (9 μmol/L) was applied to treat A549 cells for 6 h, and the total protein was collected and extracted. The peptide was digested by trypsin and labeled with TMT, and then fractionated by HPLC. The phosphorylated peptides were enriched with IMAC-Fe, and finally subjected to mass spectrometry analysis. Library identification and quantification of phosphorylated peptides obtained by mass spectrometry were processed using MaxQuant software, to further analyze the functions and pathways of differentially expressed phosphorylated proteins by combining with bioinformatic analysis. Results: Through IPA analysis of phosphorylated proteins in the normal control group and the antibacterial peptide merecidin treatment group, 753 differentially phosphorylated proteins in mericidin treatment group were screened out under the conditions of |Fold Change|≥2 and P<0.05, including 229 significantly up-regulated genes and 417 down-regulated genes. Among them, the differentially expressed proteins related to apoptosis included RB1, MAPK1, ARAF, PTK2, FOXO, MARCKSandsoon.Theresultsofbiologicalprocessanalysisshowedthatdifferentiallyexpressed phosphorylated proteins were mainly concentrated in cell signal transduction, degradation and transport of nucleic acid, and cellular energy metabolism, protein translation and synthesis, and cytoskeleton formation etc. The enrichment results showed that the differentially expressed phosphorylated proteins were mainly involved in apoptosis-related MAPK, ErbB, PI3K-Akt, and Ras signaling pathways. Protein-protein interaction analysis indicated the associations among apoptosis-related proteins PTK2, PRKCA, MA2PK2, MAPK1, and LMNA. Conclusion: The antibacterial peptide merecidin may induce apoptosis and alteration of other cell functions by affecting a variety of genes and signaling pathways such as RB1, MAPK1,ARAF, PTK2, FOXO and MARCKS etc.